SMCJ28C Transient Voltage Suppressor Diode – Equivalent & Substitute Parts

Part Overview

The SMCJ28C is a bidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 28V reverse standoff voltage with a 47.67V maximum clamping voltage at peak pulse current of 33.1A, housed in a DO-214AB (SMC) surface mount package. The SMCJ28C is classified as obsolete; equivalent and substitute parts from active manufacturers are available to maintain design continuity and ensure supply chain reliability.

Key Parameters

Parameter	Value	Unit
Reverse Standoff Voltage (Typ)	28	V
Breakdown Voltage (Min)	29.48	V
Clamping Voltage (Max) @ Ipp	47.67	V
Peak Pulse Current (10/1000µs)	33.1	A
Peak Pulse Power	1500	W
Operating Temperature Range	-55 to 150	°C
Package Type	DO-214AB (SMC)	—
Mounting Type	Surface Mount	—
Bidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SMCJ28C is determined by strict alignment of electrical and mechanical parameters. The following criteria define valid equivalents and substitutes:

Primary Substitution Criteria:

Reverse standoff voltage: 28V (fixed)
Breakdown voltage minimum: ≥29.48V
Package type: DO-214AB (SMC) surface mount
Bidirectional channels: 1
Mounting type: Surface mount
Operating temperature range: Must encompass or match -55°C to 150°C minimum

Secondary Electrical Parameters:

Clamping voltage at Ipp: Acceptable range 45.4V to 50V (within circuit protection requirements)
Peak pulse current: 30A to 33.1A (functional equivalence)
Peak pulse power: 1500W to 3000W (higher power ratings acceptable for same voltage class)

Compliance Requirements:

RoHS3 compliance mandatory
Moisture sensitivity level: 1 (Unlimited)

Substitute parts are grouped into two categories: Direct Electrical Equivalents (matching clamping voltage 45.4V and peak pulse current 33A–33.1A) and Higher Power Variants (66A peak pulse current, 3000W power rating, same voltage specifications).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Reverse Standoff (V)	Breakdown Min (V)	Clamp Max @ Ipp (V)	Peak Pulse Current (A)	Peak Pulse Power (W)	Temp Range (°C)	Package	Status
SMCJ28C	Littelfuse Inc.	28	29.48	47.67	33.1	1500	-55 to 150	DO-214AB (SMC)	Obsolete
SMCJ28CA	Fairchild Semiconductor	28	31.1	45.4	33.1	1500	-55 to 150	DO-214AB (SMC)	Active
SMCJ28CA-13-F	Diodes Incorporated	28	31.1	45.4	33	1500	-55 to 150	DO-214AB (SMC)	Active
SMCJ28CA-TP	Micro Commercial Co	28	31.1	45.4	33.1	1500	-55 to 175	DO-214AB (SMC)	Active
SMCJ28CAE3/TR13	Microchip Technology	28	31.1	45.4	33	1500	-65 to 150	DO-214AB (SMC)	Active
SMCJ28CE3/TR13	Microchip Technology	28	31.1	50	30	1500	-65 to 150	DO-214AB (SMC)	Active
SMLJ28CA	Bourns Inc.	28	31.1	45.4	66	3000	-55 to 150	DO-214AB (SMC)	Active
SMLJ28CA-TP	Micro Commercial Co	28	31.1	45.4	66	3000	-55 to 175	DO-214AB (SMC)	Active
SMLJ28CAE3/TR13	Microchip Technology	28	31.1	45.4	66	300	-55 to 150	DO-214AB (SMC)	Active

Engineering Selection Recommendations

Direct Electrical Equivalents (Recommended Primary Substitutes):

SMCJ28CA (Fairchild Semiconductor), SMCJ28CA-13-F (Diodes Incorporated), SMCJ28CA-TP (Micro Commercial Co), and SMCJ28CAE3/TR13 (Microchip Technology) provide direct functional equivalence to the SMCJ28C. All maintain 28V reverse standoff voltage, 45.4V clamping voltage, and 33A–33.1A peak pulse current within the 1500W power rating. These parts are active products with ROHS3 compliance and MSL 1 rating. Selection among these options depends on packaging format (tape & reel vs. bulk) and temperature range requirements. SMCJ28CA-TP and SMCJ28CAE3/TR13 offer extended upper temperature limits (-55°C to 175°C and -65°C to 150°C respectively), suitable for elevated ambient applications.

Higher Clamping Voltage Variant:

SMCJ28CE3/TR13 (Microchip Technology) maintains the 28V standoff voltage but increases clamping voltage to 50V with reduced peak pulse current of 30A. This variant is suitable for applications requiring higher transient voltage suppression margins while accepting lower current handling capacity.

Higher Power Variants (Enhanced Current Handling):

SMLJ28CA (Bourns Inc.), SMLJ28CA-TP (Micro Commercial Co), and SMLJ28CAE3/TR13 (Microchip Technology) provide 66A peak pulse current and 3000W power rating while maintaining 28V standoff and 45.4V clamping voltage. These are appropriate for circuits requiring enhanced surge current capacity. SMLJ28CA-TP offers the widest operating temperature range (-55°C to 175°C). All higher power variants are active products with full compliance certifications.

Compliance & Supply Considerations:

All recommended substitutes are ROHS3 compliant with MSL 1 rating. Fairchild Semiconductor SMCJ28CA offers the highest inventory availability (34,100 pcs). Microchip Technology variants (SMCJ28CAE3/TR13, SMCJ28CE3/TR13, SMLJ28CAE3/TR13) provide extended temperature ranges and are available in tape & reel packaging. Selection should prioritize active product status and compliance certifications over obsolete alternatives.

Frequently Asked Questions (FAQ)

Q: Can SMCJ28CA directly replace SMCJ28C without circuit modification?

A: Yes. SMCJ28CA maintains identical reverse standoff voltage (28V), peak pulse current (33.1A), and power rating (1500W). The clamping voltage is 45.4V versus 47.67V on the original; this 2.27V difference is within acceptable circuit protection tolerances for general-purpose applications. Verify circuit design margins before substitution in critical applications.

Q: What is the difference between SMCJ28CA and SMLJ28CA?

A: Both maintain 28V standoff and 45.4V clamping voltage. SMLJ28CA provides double the peak pulse current (66A vs. 33.1A) and double the power rating (3000W vs. 1500W). SMLJ28CA is suitable for higher surge current environments; SMCJ28CA is appropriate for standard protection requirements. Package and mounting type are identical (DO-214AB SMC).

Q: Are tape & reel packaged parts (SMCJ28CAE3/TR13, SMLJ28CA-TP) functionally equivalent to bulk packaged variants?

A: Yes. Tape & reel packaging affects only handling and assembly processes, not electrical performance. SMCJ28CAE3/TR13 and SMCJ28CA-TP are electrically identical to their bulk-packaged counterparts. Select based on manufacturing assembly requirements and inventory management practices.

Q: Why does SMCJ28CE3/TR13 have a higher clamping voltage (50V) than other substitutes?

A: SMCJ28CE3/TR13 is a variant within the SMCJ28 series designed for applications requiring higher transient voltage suppression margins. The 50V clamping voltage provides additional protection headroom at the cost of reduced peak pulse current (30A vs. 33.1A). Use this variant only if circuit design specifically requires higher clamping voltage.

Q: Can I use SMLJ28CAE3/TR13 as a substitute if my circuit only requires 1500W peak pulse power?

A: SMLJ28CAE3/TR13 is rated for 300W peak pulse power, which is below the 1500W requirement of the original SMCJ28C. This part is not suitable for direct substitution in circuits requiring 1500W transient energy dissipation. Use SMLJ28CA or SMLJ28CA-TP instead, which provide 3000W rating.

Q: What temperature range should I select for extended ambient applications?

A: For operating environments exceeding 150°C, select SMCJ28CA-TP or SMLJ28CA-TP (both rated -55°C to 175°C). For standard temperature ranges, SMCJ28CA or SMCJ28CAE3/TR13 are appropriate. Verify that selected part's temperature range encompasses your circuit's maximum junction temperature under worst-case conditions.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts listed carry ROHS3 compliance certification and MSL 1 (Unlimited) moisture sensitivity rating, meeting current environmental and reliability standards.

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